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ICS3 Exam Study Guide: Note: For Unit 9 Consult the last test and Unit 9 Makeup Quiz Assign. Unit One - Major Programming Languages - Programming Key principals: Sequence, selection and repetition - Artificial Inteligence and "the singularity" - Hardware, speed (milli, micro, nano, pico, femto, atto, zepto) and capacity (Bit, Byte, Kilo, Mega, Giga, Tera, Peta, Exa, Zetta, Yotta) Units Two and Three - Why use Python Why use Python? - What is an interpreted language? - What is a program? - What is debugging? - kinds of errors (Syntax errors, Runtime errors, semantic ( or logic) errors - Formal and natural languages Unit Four - Variables, expressions and statements - Values and types (str, int and float ie >>> type("Cowabunga") <type 'str'>) - assignment statement creates new variables and gives them values ie >>> message = "What's up, Doc?", >>> n = 17 - print statement - Variable names rules: - can contain both letters and numbers, but they have to begin with a letter.) Although it is legal to use uppercase letters, by convention we don't. If you do, remember that case matters. Bruce and bruce are different variables. - underscore character (_) can appear in a name, no keywords allowed - Python has twenty-nine keywords: and def exec if not return assert del finally import or try break elif for in pass while class else from is print yield continue except global lambda raise - Statements (an instruction that the Python interpreter can execute) - Expressions (a combination of values, variables, and operators) - Operators and operands (special symbols that represent computations like addition and multiplication) (ie hour*60+minute minute/60 5**2 (5+9)*(15-7) ) -Comments # and ''' percentage = (minute * 100) / 60 - Destructive read in - Concatenation - Escape sequences (ie \n \t) Unit Five - Operators and functions for strings a = b + c concatenate b and c a = b * c b repeated c times a[0] the first character of a len(a) the number of characters in a - String operations - Slicing Strings ie aStr = "This is a string" print aStr[0] #print T print aStr[0:4] #print This print aStr[:4] #print This print aStr[10:] #print string - length of the string print len(aStr) - input and raw_input commands Unit Six - Indentation - Decisions ie if / elif / else To compare things in Python: a < b True if a is less than b a <= b True if a is less than or equal to b a > b True if a is greater than b a >= b True if a is greater than or equal tob a == b True if a is equal to b a != b True if a is not equal to b Most conditions are comparisons of one object with another. A=3 B=4 if B > A: print A # begin group print B print (A + B) # end group A = 6 # not part of above group print A Note the difference between a double equal sign and a single one. A == B -- used to determine if A and B are the same -- no change of values A = B -- used to turn A in the same value as B -- changes of value are made. - Combining conditions using and / or - The defualt statement (when no others are true) ie else: Unit Seven and Eight Strings, Lists & Loops - String Methods (most basic way to manipulate strings) len(), replace(), count(), find(), split(), join(), upper(), lower(), capitalize(), title(), swapcase(), isdigit(),isupper(),islower(),istitle(),isalnum(),isalpha(), endswith(),append(), reverse(), remove(), sort() - Lists: a variable-like object that can hold multiple pieces of information that are indexed Example 1: x=[‘A’,’B’ ,’C ‘,’D’] print x[2] # will put C on the the screen – note a list index starts at 0 Example 2: L = ['spam', 'Spam', 'SPAM!'] L[0:2] = ['eat', 'more'] # slice assignment: delete+insert print L # replaces items 0, 1 ['eat', 'more', 'SPAM!'] Example 3: (break up a ) x=list('word') print x >>>['w', 'o', 'r', 'd']: - Repetition: for loop Example 1: for count in range(1,11): print count, # the comma is used to keep numbers on the same line >>> 1 2 3 4 5 6 7 8 9 10 Example 2: (what happens with the range command: >>> range(-32, -22) result: [-32, -31, -30, -29, -28, -27, -26, -25, -24, -23 ] >>> range(5,21) result: [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20] >>> range(21,5) result: [] - for loop and accumulator (accumulators are used to add up numbers) list = [2,4,6,8] sum = 0 for num in list: sum = sum + num # accumulator print "The sum is:", sum >>> The sum is: 20 - for loops are used to add items to an array (using append and to print out indicidual elements using the loop index. (see "bands example in tutorial) - Random numbers: requires importing the random module Example: import random pick = random.randint(1, 15) # selects one random integer from 1 to 15 print pick